Process of producing desulfurized coke from petroleum



Jan. 12, 1960 G. c. .JoHNsoN x-:T AL

PROcx-:ss OF PROOUOING DESULFURIZED COKE FROM PETROLEUM Filed Feb. 1s, 1957 .Sg'gfmundf [1f/fasi BY M ATTORN United States Patent O PROCESS OF PRODUCING DESULFURIZED COKE FROM PETROLEUM` George C. Johnson and Sigmund J. Lukasiewicz, Woodbury, NJ., assignors to Socony Mobil Oil Company, Inc., a corporation of New York Application February 13, 1957, Serial No. 639,945

Claims. (Cl. 208-106) This invention relates to the production of petroleum coke of low sulfur content from petroleum residua of high sulfur content.

In the manufacture of petroleum products the customary practice involves the separation of the crude petroleum oil into various fractions or cuts having limited boiling range, thereby providing products suitable for speciic purposes. The prime products'are naphtha and the distillate fuel oils useful as heating oil and diesel fuels. However, many otheruseful products are obtained from petroleum, including a hard brittle coke having a low ash content.

After the light products have been removed from the crude oil, there remains a heavy viscous liquid which is characterized as residuum. In one form of the conventional coking process the residuum is charged to a distillation tower with the overhead from a coker land the mixture separated into gas, gasoline, gas oil and residuum. The residuum is removed from the bottom of the distillation tower, pumped through a furnace and charged to the coker. A typical coking temperature is about 900 F. and a typical pressure is 60 p.s.i.g. The finished coke is very much in demand and the market is continually increasing. Petroleum coke is a major raw material for making anodes for the aluminum industry. Anodes for use in this industry should be low in ash and sulfur.

As crude sources are being continually exhausted, more and more crudes having a high sulfur content are being charged to processing equipment throughout the world to provide desired products. Among these are such crudes as Santa Maria'Valley, West Cat Canyon, Kuwait and Slaughter. These crudes yield coke containing more than 2 percent Sulfur and this amount is excessive for c ICC Figure 2 is a plot of weight percent sulfur in the coke produced versus coking temperature for a given high sulfur residuum.

Figure 3 shows the effect of temperature on the desulfurization of coke.

Referring to Figure l, petroleum residuum obtained from atmospheric or vacuum topping of the crude is charged to the distillation tower 10 through the path'11. Hot vapors from the coker 18 are introduced into the tower 10 through the path 9 to heat exchange with the residuum and raise the temperature of the residuum. The gas and gasoline vis., the lightest products, are removed overhead through the path 12. A somewhat heavier cut, such as a gas oil, is removed from the distillation tower 10 through the path 13. The remaining heavy product or residuum is removed from the bottom of the distillation tower 10 through the path 14 and introduced into a mixer 15. The sodium carbonate is preferably crushed or powdered rst and then introduced into the mixer 15 through the path 16. The mixture of residuum and sodium carbonate is then transferred through the path 17 to the calciner coker 18.

Although coking will generally take place at a satisfactory rate at about 900 F. and 60 p.s.i., the temperature in the calciner coker is maintained substantially `above 900 F. in this process, for example, 1400 F.

being most suitable. Hot gases can be used to heat the calciner coker to this temperature. After a suitable period of time, the coke is removed from the calciner coker and transferred through the path 19 to the washer y, 20. Water is introduced into the washer 20 through the utent of the coke is shown on Figure 2.

many uses, such as, for example, the electrodes in the furization in a single operation. The coke produced is provided in commercially acceptable form.

The object of this invention is to provide a process for producing a low sulfur content coke product from a high sulfur content crude.

A further object of this invention is to provide a simpliiied process for directly producing a low sulfur content coke from a petroleum which is high in sulfur.

These and other objects will become clear from a review of the following detailed description of the invention.

Figure 1 is a block diagram of the improved process which is used in the following detailed description.

path 21. The water solution is removed through the path 22 and finally the desulfurized product coke is removed through the path 23.

The effect of coking temperature upon the sulfur con- It is seen that correct temperature is important and that'lowest sulfur content occurs at or 'about l400 F. At lower temperatures or higher temperatures the product coke contains more sulfur. The graph shown on Figure 2 was prepared 'from data obtained by coking a residuum containing about 6.41% sulfur. The 1400 F. temperature is also the optimum in the desulfurization of coke, as shown in Figure 3.

The amount of sodium carbonate to be used depends upon the amount of sulfur present in the residuum. The usual operating range is about 0.7 to 7.2 lb. sodium carbonate for each pound of sulfur which would be present in the coke produced from the residuum if no sodium carbonate were present. For example, if the residuum yields 14% of coke containing 5.16% sulfur, the usual amount of sodium carbonate used would be 0.51 to 5.2

v lb. per 1001b. of residuum.

The optimum operating conditions are tabulated 'as follows:

Preferred Range Broad Range Temperature, F 1,300-1,500 1,100-1 ,800. Pressure Atm 0.1 atm-50 atm. Ti'ue at Reaction Temo 15-60 min 1 mim-4 hrs. Amount of Sodium Oarbon- 0.7-7.2 lb./lb. of 0.7 or greater lbs./ ate. sulfur in coke lb. of s'llfur in made without coke mafie with NazC O3 present. out NazOOa.

present.

While the process is primarily adapted for use in preparing low sulfur content coke from liquid petroleum residuum, it can also be used on residuum obtained from shale or from tar sands. The invention is particularly useful when the residuum without carbonate would yield a coke containing at least 2% sulfur.

rizatwo steps. ith the sodium he coking and desulfu ed w Coke

siduum may be carried out Sulfur in Product Yield As an alternative process t Sulfur t. Percent tion of the re For example, the residuum may be mix Time, Charge,

Coking Table I Amount of Added,

t. Percent Table I below shows the Material Material Tem Added Charge Maria Valley NaiCOa Residu The invention was tested using 72% Santa Maria residuum with sodium carbonate. results Run No.

38 72% Santa quiearbonate-lab. preparation, quicarbonate-commercial purified needles. quicarbonate-O-lo mesu (commercial).

1 This is a West Cat Canyon, California crude.

7 Average of 1402 and 1418* F.

3 Sodium ses 4 Sodium ses Sodium ses Sodium sesquicarbonate-commercial below 200 mesh.

ditions for conducting the process in two stages are as follows:

temperature is about ll-l800 F. and the reaction time is about l minute-4 hours and the amount of sodium carbonate is 0.7 or greater lbs/lb. of sulfur in the coke Preferred Broad made without sodium carbonate present and the pressure 5 during reaction is about 0.1 atmosphere-50 atmospheres. gemuiitstage s3nJ93o...: soo-1,000. 6. Claim 4 further characterized in that the coking Ssilulebro: i ggf'g/SlJ/- Ef-m" lgfg'f/m temperature is about l300-1500 F. and the reaction suifurirr coke 1b. time is about 15-60 minutes and the amount of sodium gglgltgfoul carbonate is about 0.7-7 .2 lb./lb. of sulfur in coke made gemp.,dr.,zndstage Leno-1,5300 inne-1,800. 10 without sodium carbonate present and the pressure is 1me,2n stage 15-60111111 1min-4ms. about atmospheric.

7. The method of producing a low sulfur petroleum The Sodium carbonate is Preferably used in the form co ke from a high sulfur petroleum residuum which comof a hn@ powder although small lumps can he used Suc, prises the steps of mixing with the residuum a material cessfuuy The coke from the 10W temperature Stage 15 selected from the group consisting of sodium carbonate, should not be water-washed nor removed from the coker Sodium bicarbonate, 'Sodium sesquicarbonate, Sodium Cafby hydraulic means, otherwise, sodium carbonate will be honate monohydrate, sodium carbonate heptahydrate and lost. The pressure is usually about atmospheric pressure Sodlum Carbonate decahydrate, subjecting the mixture to in the high temperature step, The coke from the high low temperature coking conditions and then subjecting temperature stage is preferably crushed before washing the mixture to a substantially higher temperature, sufbut may be used as lumps with consequent added dif. cient to electively reduce the sulfur content of the iinculty in removing the salts by Washing with water. ished coke below the amount which would be present in Table III illustrates the invention as a two-stage process. the Coke if the carbonate were not used, and washing Table III Sulfurin Amt.of Sulfur-in Coke Charge, Material Material Temper- Product Yield, Run Charge Wt. Per- Added Added, ature 1st Coke,Wt. Wt. No. cent Wt. Per- Stage Percent Per- Cent Cent 67-.-. Santa Maria Valley Crude 4. 65 None 916 5.57 12.6 o 4.65 None 930 5.64 10 64A-- 72% Santa Maria Yalley Residuum.. 6. 41 NaCOg..- 5 880 Sulfuru Amt. of Coking Sulfurin Coke Overall Coke Run Charge, Material Material Temp., Product Yield, Yield Basedon No. Charge Wt. Per- Added Added, F. 2nd Coke,Wt. Wt. Per- Crude Step 1, i

cent Wt. Per Stage Percent cent and Step 2, Wt.

cent Percent 75 Coke From Run 5.57 Nrme. o 1,404 4.83 92 12 36 Cgirre From Run 5.64 Narco,...v 20 1,405 2.88 91 e 6413.-.- Cil'From Run Nnne 1,405 3.43 l27 19 l Reflux liquid returned to eoking operation. i Step #1 plus Step #2. We claim: l the product to eiect removal of salts from the coke 1. The method of producing a low sulfur petroleum product. coke from a high sulfur petroleum residuum which com- 8. Claim 7 further characterized in that the mixture prises the steps of mixing with the residuum a material is first heated to a temperature of about 800-l000 F., selected from the group consisting of sodium carbonate, the pressure being maintained at about 1A() atmospheresodium bicarbonate, sodium sesquicarbonate, sodium car- 50 atmospheres, the amount of carbonate being at least bonate monohydrate, sodium carbonate heptahydrate, so- 0.7 lb./lb of sulfur in coke made without carbonate, and dium carbonate decahydrate and sodium hydroxide and the material is then heated to about 1100-1 800 F. for a subjecting the mixture to high temperature coking conperiod about 1 minute-4 hours, whereby a coke is proditions to produce a petroleum coke, washing the coke duced of substantially reduced sulfur content. formed to effect removal of sulfur salts, whereby a pe- 9. Claim 7 further characterized in that the mixture troleurn coke is produced having a substantially reduced iS first heated to a temperature of about SOO-930 F., the sulfur contentfrom that of the residuum from which it 6 pressure is maintained at about 60 p.s.i., the amount of is formed. 0 carbonate is about 0.7-7.2 lb./lb. of sulfur in coke made 2. Claim 1 further characterized in that the coking Without carbonate, and the material is then heated to temperature is about 1100-1800" F. about l300-1500 F. for about 15-60 minutes, whereby 3. Claim 1 further characterized in that the coking a coke is produced of substantially reduced sulfur contemperature is about 1300-1500 F. tent.

4. The method of producing a low sulfur petroleum l0. Claim 9 further characterized in that the carcoke from a high sulfur petroleum residuum which combonate material is sodium carbonate. prises the steps of mixing with the residuum at least a sucient amount of sodium carbonate in particle form, References Cited m the me of thls Patent subjecting the mixture to an advanced temperature for a UNITED STATES PATENTS sufiicient period of time to produce a petroleum coke 2,768,939 Mason et aL Oct' 30, 1955 having a Substantially I OWer Sulfur content by Weight 2,814,588 Hutchings Nov 26,1957 than would be provided if the sodium carbonate were not present, and washing the coke formed to eiect removal OTHER REFERENCES of sulfur-containing salts from the coke. Ghosh et al.: Desulfurization of Coal During Car- 5. Claim 4 further characterized in that the coking 75 bonization, Ind. Eng. Chem., 42, 1550-8, August 1950. 

1. THE METHOD OF PRODUCING A LOW SULFUR PETROLEUM COKE FROM A HIGH SULFUR PETROLEUM RESIDUUM WHICH COMPRISES THE STEPS OF MIXING WITH THE RESIDUUM A MATERIAL SELECTED FROM THE GROUP CONSISTING OF SODIUM CARBONATE, SODIUM BICARBONATE, SODIUM SESQUICARBONATE, SODIUM CARBONATE MONOHYDRATE, SODIUM CARBONATE HEPTAHYDRATE, SODIUM CARBONATE DECAHYDRATE AND SODIUM HYDROXIDE AND SUBJECTING THE MIXTURE TO HIGH TEMPERATURE COKING CONDITIONS TO PRODUCE A PETROLEUM COKE, WASHING THE COKE FORMED TO EFFECT REMOVAL OF SULFUR SALTS, WHEREBY A PETROLEUM COKE IS PRODUCED HAVING A SUBSTANTIALLY REDUCED SULFUR CONTENT FROM THAT OF THE RESIDUUM FROM WHICH IT IS FORMED. 